1. Field of the Invention
The present invention relates to a resist stripper used in a resist stripping step carried out during a process of forming Al interconnections, W interconnections, Cu interconnections, and metal gates used in a semiconductor integrated circuit. The present invention further relates to a method of manufacturing a semiconductor device using the resist stripper.
2. Background Art
Two characteristics are desired in removal of resist residues; namely, sufficient removal of resist residues and avoidance of etching the material of interconnection and the material of an interlayer insulation film.
In a device using a current Al interconnection, the extent of removal of residues or demand for etching specifications differs from one process to another. For this reason, a chemical used for an operation following processing of Al interconnections differs from that used for an operation following etching of holes.
Against such a backdrop, a variety of types of strippers are required for removing resist residues, thus resulting in an increase in manufacturing costs. For this reason, removal of resist residues through use of a single chemical during the process of forming Al interconnections is expected.
In a process of removing resist residues following a process of processing Al interconnections of a recent minute device, large problems are posed by prevention of dissipation of W plugs, an increase in the resistance of an interconnection which would be induced by etching of AlCu, and prevention of decline in the reliability of interconnections. For this reason, a desire exists for developing a stripper for removing resist residues (hereinafter referred to simply as xe2x80x9cresist-residue stripperxe2x80x9d) which satisfies the above-described specifications, can be used for processing operations subsequent to etching of Al interconnections and etching of holes, and can contribute to cost reduction.
The process of removing resist residues is also inevitable in processing of Al interconnections, as well as in an operation following an operation for processing W interconnections which have already been used, following an operation for processing Cu interconnections which is considered to be applied to a device in the future, and following an operation for processing a metal gate formed from metal material other than conventional poly-Si or WSi. Even in these processing operations, a desire exists for developing a resist-residue stripper which satisfies requirements; that is, a sufficient characteristic of removing residues, and avoidance of etching of the material of an interconnection and the material of an interlayer insulation film.
According to one aspect of the present invention, in a method of manufacturing a semiconductor device, either of an aluminum film, a tungsten film or a copper film is formed on a base layer laid on a substrate. A pattern of said aluminum film, a tungsten film or a copper film is formed from said aluminum film, a tungsten film or a copper film through use of a resist pattern and by means of photolithography. Further, the resist is removed through use of a chemical which contains an organic acid or a salt thereof and water and which has a pH below 8.
According to another aspect of the present invention, in a method of manufacturing a semiconductor device, either of an aluminum film, a tungsten film or a copper film is formed on a base layer laid on a substrate. A pattern of said aluminum film, a tungsten film or a copper film is formed from said aluminum film, tungsten film or copper film through use of a resist pattern and by means of photolithography. An interlayer dielectric film is formed on said pattern of an aluminum film, a tungsten film or a copper film. A hole pattern is formed in said interlayer dielectric film so as to reach said pattern of an aluminum film, a tungsten film or a copper film, through use of another resist mask and by means of photolithography. Thereafter, the resist is removed through use of a chemical which contains an organic acid or a salt thereof and water and which has a pH below 8.
According to another aspect of the present invention, in a method of manufacturing a semiconductor device, a composite metal film is formed on a base layer laid on a substrate. A pattern of said composite metal film is formed from said composite metal film through use of resist pattern and by means of photolithography. Further, the resist is removed through use of a chemical which contains an organic acid or a salt thereof and water and which has a pH below 8.
Other and further objects, features and advantages of the invention will appear more fully from the following description.